Model of Public Support for Railway Sidings as a Component of the Sustainable Development of Rail Freight Transport

Abstract

Rail freight transport represents a key tool for the decarbonisation and greening of logistics chains within the European Union. However, in many Central and Eastern European countries, including the Slovak Republic, a vast network of industrial sidings (rail spurs) remains underutilized or neglected. This reduces the overall efficiency of transport infrastructure and represents a missed opportunity for sustainable transport development. This paper proposes a comprehensive public support model for rail sidings. It combines legislative analysis, a tax incentive mechanism, and analytical evaluation of transport and investment benefits. The methodology calculates the potential transport output of reactivated sidings. It also introduces three quantitative indexes: the Siding Efficiency Index (IEV), the Comprehensive Importance Index (ICV), and the Reactivation Value Index (RVI). These indicators allow for a structured, objective assessment of siding suitability for restoration and public funding. We applied the model to a sample of five sidings in Slovakia, deriving values from expert evaluations. The results show that objective indicators, performance estimates, and targeted public support can identify infrastructure with high revitalization potential. These tools help reintegrate such assets into sustainable transport flows. The analysis indicates that reactivating 5% of existing sidings could shift hundreds of thousands of tonnes of freight annually from road to rail. This change would reduce emissions and improve network efficiency.

1. Introduction

A railway siding is a specialized segment of infrastructure that provides a direct connection between industrial, storage, or manufacturing facilities and the public railway network. Sidings play a crucial role in the initial and final stages of logistics chains, where the transportation, handling, and transfer of goods are the most time- and cost-intensive. Their ability to eliminate the need for intermediate road transport makes them a key instrument in promoting environmentally friendly, economically viable, and spatially efficient freight transport.

In the context of the European Union’s climate and mobility goals, the importance of railway sidings is once again coming into focus. The EU has long supported the shift in freight transport from road to rail and is actively seeking ways to improve the efficiency of servicing industrial and logistics zones through intermodal and combined transport solutions. Despite this policy emphasis, siding infrastructure in many countries, particularly in Central and Eastern Europe, remains underutilized, lacking strategic management, proper inventory, and targeted support.

In the Slovak Republic, as well as in several other Central and Eastern European countries such as the Czech Republic, Poland, Hungary, and Romania, the railway siding sector has long suffered from a lack of attention in national transport policy [1]. Owners have allowed many sidings to become technically outdated, poorly maintained, or administratively decommissioned. Moreover. The Ministry of Transport has not created a unified national database to monitor their condition, assess their potential, or identify reactivation opportunities. Siding owners are also confronted with a non-transparent regulatory framework, a lack of investment incentives, and disadvantageous tax conditions.

In contrast, several Western European countries have undertaken systematic efforts to restore and support railway sidings as infrastructure extensions of the public rail network [2]. In Austria and Germany, targeted subsidy schemes are in place; Poland has integrated sidings into its strategic rail transport documents; and France has introduced tax incentives for businesses that use sidings as entry points into the rail freight system. These approaches demonstrate that a well-balanced combination of legislative, fiscal, and technical instruments can enhance the attractiveness of siding-based transport and restore its functionality in line with sustainability objectives [3,4].

The novelty of this paper lies in the development of a comprehensive, transferable public support model for railway sidings that integrates three distinct components: (i) a legislative and regulatory analysis identifying barriers and enablers for siding revitalization [5]; (ii) a fiscal support instrument in the form of a tax incentive mechanism; and (iii) a new quantitative evaluation framework introducing three original indices—the Siding Efficiency Index (IEV), the Comprehensive Importance Index (ICV), and the Reactivation Value Index (RVI). We developed these indices—absent in the previous literature—to provide a structured, objective, and data-driven method for assessing the potential of individual sidings for reactivation.

The proposed model also includes the concept of a national database of unused railway sidings, envisioned as a digital tool to support planning, financing, and decision-making processes. By quantifying potential modal shift impacts, estimating environmental benefits, and applying an index-based assessment, this study contributes new methodological and policy-relevant insights to the field of sustainable freight transport. Although developed with a focus on the Slovak Republic, the approach is applicable to other EU countries with a similar siding network structure, supporting the broader goals of the European Green Deal and the UN Sustainable Development Goals (SDGs).

2. Literature Overview

Railway sidings represent a key element in connecting industrial, manufacturing, and distribution facilities with the public railway network. Their primary function is to enable the loading and unloading of goods directly at the point of origin or consumption, thereby minimizing the need for road transport in the first and last segments of freight journeys. As noted by several authors [6,7], the availability of functional sidings contributes to modal shift—from road to rail, which is one of the core objectives of EU transport policy. However, the academic literature also highlights a long-term decline in siding utilization, driven by the liberalization of the rail market, low levels of investment, and increasing complexity of logistics chains [8].

As noted by several authors [6,7], the availability of functional railway sidings contributes to modal shift—from road to rail—which is one of the key goals of EU transport policy. This approach is fully aligned with the European Commission’s Strategy for Sustainable and Smart Mobility, which promotes the development of railway infrastructure, including sidings as important feeder points into the core network [9]. The strategy also emphasizes the need for investment in terminals, improved connectivity, and support for environmentally friendly forms of freight transport as tools to reduce the carbon footprint and strengthen the competitiveness of rail.

Several studies identify common barriers that hinder the broader use of railway sidings in practice. These include the high maintenance costs borne solely by private owners, the absence of tax incentives, and the insufficient integration of sidings into strategic railway infrastructure planning [10]. Some authors also point to the lack of central registers and state support—sidings are often viewed merely as private industrial facilities rather than as integral components of the national logistics system [impact assessment]. In this context, the OECD (2019) recommends shifting the perception of sidings to a form of infrastructure with public value.

In recent years, several European countries have introduced targeted support mechanisms for the development of railway sidings. In Austria, an investment subsidy system is in place for the construction or rehabilitation of sidings [11]. In Germany, simplified permitting procedures and technical consulting services have been implemented [12], and in France, tax incentives are provided to companies that use railway sidings as entry points into the public rail network [13]. Moreover, within the framework of its intermodal strategy, the European Commission recommends integrating sidings into national transport plans as infrastructure elements with high added value [14].

Despite these positive examples, there are significant differences among countries in their approach to railway siding, ranging from fully supported models to liberalized markets. This variability provides both inspiration and challenges when attempting to transfer best practices to the context of the Slovak Republic.

While qualitative assessments of infrastructure projects are common in practice, the academic literature is placing increasing emphasis on the use of quantitative indicators in decision-making related to public funding. Studies by Martens and Di Ciommo [15], as well as methodologies developed by the World Bank [16], present models that link operational performance with assessments of strategic importance. Such approaches enhance the transparency of public resource allocation and form the methodological foundation for this article, which proposes the introduction of the Siding Efficiency Index (IEV) and the Comprehensive Importance Index (ICV) as tools for evaluating the eligibility of railway sidings for state support.

3. Current State of Railway Sidings

Currently, under the European Union’s environmental and transport policies, there is a strong emphasis on the restoration and modernization of railway sidings—primarily due to the higher environmental sustainability of rail transport compared to road transport. The growing focus on ecological aspects within transport policy may lead to increased interest in rail freight, including the use of sidings as an essential component of logistics chains [17,18,19].

A key factor for the further development of railway sidings is investment in the modernization of rail infrastructure, as well as the digitalization and automation of operational processes. These measures can enhance the efficiency of siding utilization and enable better integration into intermodal transport systems [20]. As a result, such steps may not only improve logistics processes and increase the competitiveness of rail freight transport, but also strengthen the role of railway sidings within national transport systems.

Authorities have issued 359 operating permits for railway sidings in the Slovak Republic. Of these, 265 sidings are actively served, meaning that regular rail freight operations take place—primarily serving industrial enterprises, logistics centers, energy companies, and agricultural and construction facilities. The authorities classify another 65 sidings as inactive because their owners have made economic, technical, or strategic decisions to cease operations. The remaining 29 sidings are designated as “operational,” meaning they are not regularly served but are technically capable of handling rail transport on demand or in a limited capacity [16].

Railway sidings represent a core component of freight rail infrastructure, as they provide direct access for rail transport to industrial, storage, and logistics facilities. In Slovakia, sidings are systematically classified [21] within professional practice and infrastructure management based on various criteria, with the operational status being one of the key factors.

In this context, two basic categories of railway sidings can be distinguished:

• Defined sidings with active service—these are sidings where the rail operator regularly performs siding operations, i.e., the shunting and transfer of railcars between the connecting station and the customer’s siding;
• Defined sidings without active service—the operator recognizes these sidings technically and formally in its system, but does not carry out siding operations during the assessment period. This may include temporarily unused or long-term inactive sidings that still hold potential for future reintegration into transport flows.

Railway operators classify sidings according to their affiliation with operational centers, based on designated services in the railway timetable (GVD) or on actual shunting operations on-site. The railway network distributes sidings among four main operational centers—Bratislava, Košice, Zvolen, and Žilina—while individual stations outside these areas serve a smaller number.

The highest concentration of active railway sidings is located in the Košice region, which represents a major industrial area of Slovakia. Many metallurgical and chemical plants, along with other strategic enterprises, utilize sidings as integral parts of their logistics chains. The second area with 78 sidings is Bratislava, which, as the capital city, functions as a national transport and distribution hub. Zvolen and Žilina form additional stable centers of siding operations, primarily serving regional industries, mining, and the transport of raw materials.

Other sidings that do not fall under any of the aforementioned operational centers are often located outside the main transport corridors and are served less frequently. Nevertheless, they play a role in handling 15% of regional freight in regional logistics and represent potential for the development of targeted rail services, especially in cases where the infrastructure remains technically usable in terms of its condition. The following chart compares the number of defined services (planned according to the railway timetable) and executed services (carried out) on railway sidings. Defined services refer to scheduled operations agreed upon between the rail operator and the customer and incorporated into the official timetable. Executed services, on the other hand, reflect the actual situation; that is, the operations that were performed in practice during the reporting period. Comparing these two indicators makes it possible to analyze planning efficiency and identify potential discrepancies between expected and actual demand for siding services. The distribution of railway sidings among operational centers is illustrated in Figure 1.

The comparison between planned and executed siding services reveals significant differences across individual operational centers. The Košice Operational Center (KE) recorded the highest number of defined services (7921), yet only 3864 of them were actually carried out, indicating a substantial level of underutilized capacity. In contrast, the Bratislava Operational Center (BA) demonstrated the highest implementation rate—out of 5442 planned services, 5140 were executed, representing nearly full realization of scheduled operations. The Zvolen Operational Center (ZV) reported the lowest execution ratio, with only 1386 services performed out of 3839 planned, which may indicate limited transport demand or operational difficulties in the region. For other stations outside the main centers, the performance was also very low—only 161 services were implemented out of a scheduled 1222, suggesting limited use and potentially lower efficiency within the overall railway siding system [22].

• Analysis of Siding Service Execution Rates

An important indicator of the operational efficiency of railway infrastructure is the success rate of planned services, i.e., the proportion of services actually performed. Based on the available data, there are considerable regional differences, which will be discussed in more detail in the following section.

The highest success rate was achieved by the Bratislava operational center, where as many as 94.5% of planned services were executed, indicating the high stability and reliability of the transport processes in the region. In contrast, the lowest success rate was recorded in the group labeled “Other,” with only 13.2%, suggesting substantial underutilization of planned capacity. Other regional values were as follows:

• Košice: success rate of 48.8%;
• Žilina: success rate of 39.2%;
• Zvolen: success rate of 36.1% [22].

These figures highlight a considerable untapped potential of existing sidings, which could be activated through appropriate support measures—such as improved coordination, simplified service ordering, or the introduction of financial incentives. As further analysis shows, increasing the success rate to 90% could nearly double the number of executed services in certain regions, which would have a direct impact on shifting freight from road to rail transport.

Overall performance losses due to low execution success represent tens of thousands of services annually that are planned but not implemented. Improving efficiency to, for example, 90% across all centers could nearly double the system’s actual output—especially in Košice, Žilina, and Zvolen. Support aimed at stabilizing service processes, reducing administrative burdens, and utilizing digital tools could have a significant systemic effect, potentially increasing operational output by 15–20% and improving service reliability across regions.

4. Materials and Methods

The research methodology was designed to comprehensively assess and optimize the possibilities of public support for the reactivation of railway sidings under the conditions of the Slovak Republic. The research is based on legislative and strategic analysis, the proposal of a financial incentive mechanism, the development of a national database of unused sidings, and the quantitative modeling of transport and investment potential [17,23]. The outcome of this methodological approach is a coherent framework that enables systematic decision-making on the support and utilization of siding infrastructure in line with the objectives of environmental and regional transport policy. The methodology consists of the following steps:

• A: Analysis of the Legislative and Strategic Framework:

The research initiated with a structured analysis of the national and European legal and strategic environment. This included a review of the transport policies and strategies of the Slovak Republic and the European Union, an analysis of the applicable legislation related to railway sidings, and the identification of existing financial and tax instruments aimed at supporting transport infrastructure. Particular attention was paid to the potential for tax incentives to support investments in the rehabilitation of railway sidings, as well as to the constraints arising from ownership structures and the applicable regulatory framework.

• B: Proposal of a Tax Incentive Model for Railway Sidings

Based on the results of the legislative analysis, a tax savings model was developed for business entities undertaking the rehabilitation of railway sidings. The model assumes the possibility of deducting eligible expenses from the tax base. The calculation includes:

• Discounting future tax savings to present value;
• Assessing investment attractiveness from the perspective of a private investor.

• C: Proposal of a Tax Relief Mechanism for Infrastructure Investment

As part of the research, a concept for a national database was developed to collect information on technically preserved but currently unused railway sidings. This database includes detailed technical parameters and the current conditions of the track infrastructure, their exact location and connection to the ŽSR network, as well as potential links to industrial and logistics entities that could utilize rail access in their future operations. The database is designed as a strategic tool that provides key information for planning public support in the field of railway infrastructure renewal. At the same time, it serves as a decision-making resource for investors seeking suitable sites for logistics or industrial developments with rail access. In addition, the database enables analytical evaluation through the RVI (Reactivation Value Index), a quantitative indicator used to assess the reactivation potential of specific sidings based on their technical condition, location, and strategic relevance.

• D: Systemic Modeling of Siding Potential Using Composite Indexes

The final component of the methodology involves the development of quantitative analytical tools for evaluating the potential and efficiency of railway sidings from transport, economic, and strategic perspectives. Three main indexes were developed:

• Transport Performance Model—a basic calculation based on the expected volume of freight transport;
• IEV (Siding Efficiency Index)—quantifies the actual utilization rate and cost efficiency of a siding;
• ICV (Comprehensive Importance Index)—incorporates the strategic, environmental, and regional value of the siding.

A detailed description of the construction of these indexes, including calculation formulas and application examples, is provided in the following chapter.

The methodological framework was designed to be replicable in other European Union countries with a similar railway infrastructure structure and comparable challenges in siding utilization. At the same time, it is conceived as sufficiently flexible and open to the inclusion of additional quantitative or qualitative indicators tailored to specific national or regional contexts. Its open architecture allows for adaptation to spatial planning frameworks, environmental priorities, or specific sectoral needs, thus providing a universally applicable tool for the development of strategic transport policies.

• Calculation of CO₂ Emission Reductions

Emissions were calculated using the standard emission factor method recommended by the European Environment Agency [24]. First, the potential volume of transport shifted (in tonne–kilometers) was estimated for each reactivated siding based on current road freight volumes and distances to the relevant destinations. The tonne-kilometer values were then multiplied by emission factors specific to each mode of transport (g CO₂ per tonne–kilometer): 62 g for road transport and 22 g for rail transport, according to EEA data. The difference between these two results represents the potential for CO₂ emissions reductions.

For example, reactivating a siding that generates 10 million tonne–kilometers per year would lead to a reduction in emissions of approximately 400 tons of CO₂ per year. Where possible, the national emission factors for Slovakia, as reported by Kendra, were also used to take local transport conditions into account in the calculation.

This emission calculation is integrated into the methodological framework as part of a broader sustainability assessment. It quantifies the direct environmental benefits of siding reactivation by estimating the modal shift from road to rail and the associated reduction in greenhouse gas emissions. The use of national emission factors for Slovakia (Kendra) ensures that the calculations reflect local transport conditions and policy contexts. By embedding this step into the methodology, the study aligns with the European Union’s and Slovakia’s climate objectives, thus providing a clear link between technical feasibility, economic viability, and environmental sustainability.

5. Framework for Public Investment and Incentive Mechanisms in Siding Infrastructure

In order to support the reactivation and development of railway sidings as a key component of environmentally sustainable freight transport, it is necessary to establish a set of public policies and instruments that will incentivize both private and public entities to invest in this type of infrastructure. Given the specifics of the Slovak legal and fiscal environment, it is appropriate to combine direct and indirect forms of public support that are effective, transparent, and administratively feasible. This chapter presents a proposal of concrete measures that can be implemented within the framework of national transport policy, with a focus on tax incentives, the registration of siding infrastructure potential, and the support of strategic planning.

5.1. Indirect Public Support Through Tax Incentives for Rail Sidings

One of the effective tools of indirect public support for investments in railway infrastructure is the application of tax depreciation in accordance with applicable legislation. In the case of the rehabilitation or modernization of railway siding, business entities may deduct capital expenditures from their taxable base, thereby reducing their overall tax liability. This mechanism is legislatively stable, non-discriminatory, and linked exclusively to the activity of the entity itself, without the need to submit applications for grants. It thus represents a transparent and administratively efficient tool that allows the state to support sustainable transport solutions without direct intervention in the market environment.

The proposed model of public support for railway sidings in the Slovak Republic builds on existing possibilities within the tax legislation—specifically, the Income Tax Act No. 595/2003 Coll. This law allows businesses to classify a railway siding under depreciation group no. 5, with a depreciation period of 20 years. However, the application of this instrument requires a high level of organizational and technical readiness, including the following:

• A systematic recording of investment costs;
• The accurate classification of assets into the relevant depreciation group;
• The preparation of a long-term depreciation plan;
• Alignment between accounting and tax depreciation;
• Regular evaluation of the impact of depreciation on the taxable base and cash flow.

From the perspective of public finance theory, this represents a form of tax expenditure, which enables the government to selectively support desirable behavior—in this case, investments in an environmentally preferred mode of transport—without the need for direct spending from the state budget. Tax depreciation thus constitutes a fiscally neutral measure that promotes the long-term sustainability of the transport system.

• Case Application of a Tax Allowance

As a model example, a railway siding with a current load classification of C4 (20 t/axle) was analyzed, with plans for modernization to class D4 (22.5 t/axle). Such a reconstruction would enable the more efficient handling of freight trains, reduce the number of train movements, and result in corresponding CO₂ emission savings.

The estimated investment cost of approximately EUR 57 million was subjected to a model calculation of its impact on the company’s taxable base. Preliminary results indicate that an annual tax depreciation of EUR 2.85 million would lead to a reduction in tax liability by approximately EUR 599,000 per year, representing a substantial long-term financial saving of approximately EUR 12 million over the 20-year depreciation period. A detailed calculation, including the formula and scenario analysis, will be presented in Chapter 6—Results.

• Environmental and Systemic Significance

From an environmental perspective, this approach aligns with the goals of the European Green Deal, which promotes a modal shift in freight transport from road to rail. The introduction of tax incentives for the rehabilitation of railway sidings also contributes to the principles of the circular economy by encouraging companies to maintain and upgrade existing infrastructure rather than replace or abandon it.

5.2. Design and Implementation of a National Database for Unused Railway Sidings

The creation of a national database of disused but technically viable railway sidings represents a strategic instrument for supporting sustainable freight transport [19]. This tool aims to centralize and publicly share key information about sidings that are currently inactive yet possess reactivation potential. Such a database would serve multiple functions: enabling logistics operators, investors, local governments, and policymakers to identify opportunities for reusing existing infrastructure, thereby reducing the need for new track construction, saving public resources, and promoting environmentally responsible transport.

The core function of the proposed database is to serve as a publicly accessible registry of disused sidings, containing comprehensive information on their location, technical status, ownership, historical use, and potential for future redevelopment. This would support the broader concept of infrastructure circularity by extending the lifecycle of existing assets.

Target Users and Benefits

• Local governments: For land-use planning, zoning industrial parks, and determining whether to preserve or dismantle existing infrastructure.
• Investors and developers: To identify locations with dormant but reconnectable rail infrastructure suitable for brownfield revitalization.
• Public institutions and policymakers: As a planning and analytical tool to support modal shift strategies and reduce pressure on road infrastructure.

The database also supports decarbonization goals by facilitating a modal shift from road to rail. Reviving disused sidings could reduce truck movements, lower CO₂ emissions, and improve road safety—all of which align with the EU Green Deal and national mobility strategies.

Database Structure

Each siding record in the database would include:

• Official name;
• Geographic location and coordinates;
• Rail and road connectivity;
• Ownership and operator information;
• Current technical condition;
• Track parameters (length, gauge, load-bearing capacity);
• Historical usage and last date of operation;
• Potential reuse scenarios (e.g., logistics, storage, rail-to-road transfer);
• Supplementary data such as photos or legal notes.

The registry classifies records by status (functional but unused, temporarily out of service, abandoned, or formally decommissioned with remaining infrastructure). A standardized structure would ensure compatibility with planning systems and GIS tools.

• Operational and Economic Benefits

A preliminary cost estimate for developing and operating the database shows relatively low annual operational expenditure (EUR 132,800/year), with high strategic value in return. The implementation would increase information transparency, reduce market asymmetry, and support datadriven infrastructure policy. According to model estimates, reactivation of even 5% of currently disused sidings could shift 200,000–250,000 tonnes of cargo from road to rail annually, potentially removing 10,000–12,000 heavy truck trips per year and cutting CO₂ emissions by 15,000–20,000 tonnes.

The implementation of a national strategy for the reactivation of railway sidings has the potential to generate broad benefits across multiple stakeholder groups:

• For the state and the European Union, it enables more accurate targeting of infrastructure investments and contributes to achieving long-term climate and sustainability data objectives.
• For the railway infrastructure manager (ŽSR), it leads to higher network utilization and increased revenue through access charges for newly reactivated sidings.
• For rail operators, it opens up new routes and business opportunities by expanding the connectivity of the siding network and supporting intermodal transport.
• For industry and private investors, it simplifies location selection processes and reduces initial capital investment by providing access to pre-existing rail infrastructure.
• For the public and the environment, it helps reduce road congestion, noise, and greenhouse gas emissions, while also improving traffic safety and promoting sustainable freight mobility.

5.3. Quantitative Assessment of Railway Siding Potential

For the purpose of quantifying the efficiency and strategic importance of railway sidings in the context of public support, three complementary indicators were developed:

(1) Transport Potential Model;

(2) Reactivation Value Index (RVI);

(3) A pair of indexes—IEV (Siding Efficiency Index) and ICV (Comprehensive Importance Index)—which enable comprehensive evaluation across various transport planning contexts.

5.3.1. Calculation Model for the Annual Freight Potential of Reactivated Sidings

The basic calculation formula is based on the assumption that each reactivated railway siding has a certain average transport capacity, which can be utilized at varying levels of intensity. The potential annual freight performance can be defined as follows:

P = V × p × k

(1)

where the following hold:

• P—expected annual freight volume (in tonnes);
• V—number of reactivated sidings;
• p—average annual capacity of a single siding (in tonnes);
• k—coefficient of effective utilization (0–1), reflecting unused capacity or operational limitations.

5.3.2. Reactivation Value Index (RVI)

For the purpose of selecting railway sidings with the highest potential for reactivation, we propose the introduction of the Reactivation Value Index (RVI)—a composite indicator that incorporates multiple aspects relevant to decision-making regarding the restoration of operations. The index is intended to be used as a key analytical tool within the national database of unused sidings, supporting prioritization and strategic planning for public investment and infrastructure development.

RVI = α × Ts + β × A + γ × C

(2)

where the following hold:

• Ts—technical condition of the siding (scale 0–1);
• A—attractiveness of location (e.g., proximity to main rail or road corridors);
• C—regional transport potential (e.g., volume of road freight in the surrounding area);
• α, β, γ—weighting coefficients reflecting the priorities of the state, investors, or the infrastructure manager (e.g., ŽSR).

An RVI value above a defined threshold (e.g., 0.6) serves as a criterion for eligibility for public support, inclusion in infrastructure renewal plans, or as a filtering mechanism within the national database of railway sidings. The introduction of this indicator ensures a systematic and objective approach to decision making regarding the reactivation of specific sidings.

As part of the proposed model of state support for railway sidings in the Slovak Republic, the need to quantify the performance and strategic importance of individual sidings has emerged as a key tool. For this purpose, two complementary indicators have been developed: the Siding Efficiency Index (IEV) and the Comprehensive Importance Index (ICV). These indexes enable an objective comparison of sidings in the process of setting priorities for public support and investment decisions.

5.3.3. Siding Efficiency Index (IEV)

The Siding Efficiency Index (IEV) represents the level of operational efficiency of a siding, taking into account both the actual intensity of its use and the economic cost of its operation. It is calculated using the following formula:

$$\mathrm{I}\mathrm{E}\mathrm{V}=\left({\displaystyle \frac{O_v}{O_d}}\right)\times K_n$$

(3)

where the following hold:

• O_v = number of executed siding services (e.g., per year);
• O_d = number of planned or possible siding services;
• K_n = cost coefficient, representing the average cost per service unit (e.g., EUR/service), or indexed against the national average in Slovakia.

• The interpretation is as follows:

• IEV > 1 indicates an above-average efficient siding (high utilization at reasonable cost);
• IEV < 1 suggests underutilization or excessive operational costs.

5.3.4. Comprehensive Importance Index (ICV)

The Comprehensive Importance Index (ICV) is a synthetic indicator used to evaluate the broader strategic, environmental, and regional significance of a railway siding. Unlike the IEV, which focuses on operational performance, the ICV captures contextual factors that may justify public support or prioritization in transport planning—even in cases of current underutilization.

ICV = IEC × Kv

(4)

where Kv = siding importance coefficient, which reflects factors such as strategic location (e.g., connection to the TEN-T network), freight volume, type of transported goods, number of served entities, or environmental benefits.

• The interpretation is as follows:

• ICV > 1.5 = siding with high value for public support;
• ICV 1.0–1.5 = siding of average strategic importance;
• ICV < 1.0 = siding with limited systemic contribution.

The quantification of the location attractiveness component within the ICV indicator was based on publicly available data from the Statistical Office of the Slovak Republic, the National Transport Authority, and national rail freight statistics. Key parameters included the proximity of the siding to industrial zones, logistics hubs, and mainline rail corridors. The regional transport potential component was calculated using regional freight volume data, gross domestic product (GDP) per region, and population density. When official quantitative data were unavailable, independent experts in railway infrastructure management and logistics supplemented the values. This mixed-method approach ensured that both measurable statistical indicators and operational knowledge were reflected in the evaluation process.

The presented indexes enable a transparent and quantitative assessment of the suitability of individual sidings for priority inclusion in state-supported programs (e.g., investment subsidies, tax incentives, and technical assistance). Their implementation also supports the development and strategic enhancement of the national railway siding database as a tool for sustainable transport policy.

6. Application of Proposed Public Support Tools for Railway Sidings

The effect of applying tax depreciation can be quantified using a model for calculating annual tax savings. This calculation is based on the fundamental principle of tax optimization, whereby each reduction in the taxable base through depreciation results in a proportional saving on income tax. The annual tax saving (ΔDP) can be expressed using the following formula:

$$∆\mathrm{D}\mathrm{P}=\mathit{t}\times \left({\displaystyle \frac{I}{n}}\right)$$

(5)

where the following abbreviations are used:

• ΔDP—annual tax savings [EUR];
• t—corporate income tax rate (21% in Slovakia, i.e., 0.21);
• I—total investment in the reconstruction of the railway siding [EUR];
• n—number of depreciation years according to the relevant depreciation group (20 years for sidings—group 5).

A practical application of this model, based on an investment of EUR 57,042,080.58, results in an annual depreciation of EUR 2,852,104.03. When applied to the formula, the enterprise obtains an annual tax saving of approximately EUR 598,941.85. This saving recurs throughout the entire depreciation period and allows for a consistent distribution of the tax burden over time.

This calculation confirms (

Table 1. Model calculation of the impact of tax depreciation on the tax base and tax liability.

Indicator	Value (EUR)
Total investment	57,042,080.58
Depreciation period (years)	20
Annual depreciation	2,852,104.03
Tax base before depreciation	95,447,000.00
Tax base after depreciation	92,594,895.97
Tax before depreciation (21%)	20,043,870.00
Tax after depreciation (21%)	19,444,928.15
Annual tax saving	598,941.85

) that the use of the existing tax depreciation mechanism represents an effective and predictable tool for the financial optimization of investments in railway infrastructure, without the need to draw on direct public subsidies. At the same time, this instrument helps to lower entry barriers for businesses considering the rehabilitation or modernization of sidings, in line with the principles of environmental and transport sustainability.

The data are based on a model case of siding reconstruction with a depreciation period of 20 years, in accordance with the applicable legislation of the Slovak Republic (Income Tax Act No. 595/2003 Coll.).

• Theoretical Extension of the Model: Discounting and Probability of Utilization

The basic model for calculating annual tax savings assumes a linear and full application of tax depreciation over the entire depreciation period, without taking into account the time value of money or risks related to the company’s financial performance. However, for a more comprehensive economic evaluation, the model can be extended to include elements of financial analysis, such as discounting future savings or the probability of their actual realization. The discounted cumulative tax saving over the full depreciation period can be expressed by the following formula:

$$∆{\mathrm{D}\mathrm{P}}_{\mathrm{c}\mathrm{u}\mathrm{m}}={\sum }_{t=1}^{\mathrm{n}}{\displaystyle \frac{p_{t }\times { t}_{r }\times \left(\frac{I}{n}\right) }{ (1+r{)}^t}}$$

(6)

where the following abbreviations hold:

• Δ${\mathrm{D}\mathrm{P}}_{\mathrm{c}\mathrm{u}\mathrm{m}}$—present value of expected cumulative tax savings;
• p_t—probability that the company will be profitable in year ttt;
• t_r—corporate tax rate in year ttt (can be considered constant or variable);
• I—initial investment;
• n—number of depreciation years;
• r—discount rate reflecting the cost of capital or inflation.

The discount rate applied in the calculation of tax savings was set at 3%, in line with standard practices for economic evaluation of transport investments in the European Union. This rate corresponds to the inflation-free component recommended by EUROCONTROL and the EU cost–benefit assessment methodologies, representing the time-value of money plus an appropriate risk premium

Based on these parameters, the discounted cumulative tax saving amounts to approximately EUR 7.46 million. This calculation reflects the present value of public support through tax depreciation from the perspective of the investor, and it enables comparison with other forms of public incentives. If this mechanism were implemented, the company could realistically save nearly 13% of the total investment cost over a 20-year horizon.

This model provides a more realistic assessment of the effectiveness of using tax depreciation for railway infrastructure investments, particularly in cases with long investment horizons and uncertain cash-flow development. It also opens up space for future research focused on comparing the efficiency of different forms of public support in terms of their actual financial return.

The calculations confirm that tax depreciation represents an effective and legislatively stable instrument of indirect public support for investments in the rehabilitation of railway sidings. Its main advantage lies in its ability to reduce a company’s tax burden without the need to draw direct subsidies, while the entire mechanism remains transparent and administratively simple. The model case demonstrated that with an investment of EUR 57 million, a company can achieve annual tax savings of nearly EUR 599,000, thus supporting financial sustainability and long-term planning in the field of transport infrastructure modernization.

To broaden this approach with a deeper economic evaluation, a theoretical extension of the cumulative tax-saving calculation was proposed. This extended formula incorporates the time value of money through discounting and allows for the integration of a risk component in the form of the probability that the company will generate sufficient profit in a given year to apply the depreciation. The result is a flexible calculation framework that can be used not only for ex ante investment project assessments, but also as a comparative tool when selecting the most suitable forms of public support in the rail freight sector.

The adoption of this model in decision-making related to state support for siding reconstruction could significantly contribute to a more efficient allocation of public resources, while also encouraging businesses to implement projects that enhance the environmental and logistical objectives of sustainable transport.

• National Database

To support systematic planning and the evaluation of unused but technically preserved railway sidings, a national database with a unified data structure is proposed. This structure captures key technical, geographic, operational, and strategic information for each siding, enabling classification, comparison, and quantitative analysis through tools such as the Reactivation Value Index (RVI), the Siding Efficiency Index (IEV), and the Comprehensive Value Index (ICV).

Table 2. Structure of the National Railway Siding Database—key attributes and descriptions.

Attribute	Type/Format	Description
Siding ID	Numeric/alphanumeric	Unique identifier of the siding
Official name	Text	Registered name or label of the siding
Geographic coordinates	Decimal degrees (lat/lon)	Precise GPS position of the siding
Administrative region	Text (e.g., Žilina, Košice)	Slovak region in which the siding is located
Connection to ŽSR network	Yes/No	Whether the siding is physically linked to the national rail network
Track length	Meters (m)	Total usable track length
Load-bearing class	Text (e.g., C3, D4)	Axle load class according to technical standards
Technical condition (Ts)	Float (0.00–1.00)	Expert assessment of infrastructure state
Last operational year	Year	Last known year of active rail service
Industrial function	Text	Type of connected industrial or logistics site
Reactivation potential	Text (high/medium/low)	Qualitative judgment of reuse feasibility
Reactivation Value Index (RVI)	Float (0.00–1.00)	Calculated index summarizing reactivation suitability
Additional notes/documents	Text/file/link	Photos, legal context, historical info

presents the core data fields included in the database, ensuring consistent assessment and informed decision making across all regions.

This unified structure enables the integration of the database with spatial planning tools, GIS systems, and analytical models for public support decision making. It also forms the basis for the transparent, datadriven assessment of sidings and their inclusion in strategic plans, supporting sustainable freight transport in the Slovak Republic.

The technical condition of a siding (Ts) is evaluated as a numerical variable ranging from 0.00 to 1.00, where 1.00 indicates a fully functional siding with no need for repairs, and 0.00 represents a physically dismantled or non-existent siding (

Table 3. Classification of sidings by technical condition (Ts).

Range Ts	Qualitative Marking	Status Description
1.00–0.85	Excellent condition	Operational and in use, no major defects. Regular maintenance, turnouts, sleepers and rails meet standards.
0.84–0.70	Good condition	Slight wear, occasional minor defects. Requires only basic maintenance before reactivation.
0.69–0.50	Fair condition	Noticeable wear, localized damage (e.g., potholes, rotten sleepers). Recoverable with modest investment.
0.49–0.30	Poor condition	Severe damage, deformed geometry, non-functional turnouts, damaged drainage. Requires major reconstruction.
0.29–0.01	Critical condition	Tracks impassable, overgrown, dismantled parts, no operation for over 10 years.
0	Non-existent/dismantled	Physically removed siding, no restoration possible without completely new construction.

). The evaluation is based on expert assessment of multiple technical parameters, including the condition of tracks, switches, connections, drainage, and accessibility. For the purposes of quantitative models, individual sidings are classified into six technical condition categories, each with a defined Ts value range.

For the purpose of a practical illustration of the proposed Reactivation Value Index (RVI), a model sample of five railway sidings was compiled, representing various regional and technical conditions. The selection includes sidings located in the industrial areas of Žilina, Košice, Zvolen, Bratislava, and Banská Bystrica.

For each siding, three key input parameters were quantified:

Ts—technical condition of the infrastructure (on a scale from 0 to 1);

A—attractiveness of location (based on network connection and spatial context);

C—regional transport potential (freight volumes in the vicinity, network density).

These parameters were evaluated based on expert inputs from professionals in railway infrastructure, transport planning, and logistics.

The resulting values were then integrated into the RVI calculation using the following formula:

RVI = α × Ts + β × A + γ × C

(7)

The following abbreviations are used:

• Ts—Technical condition of the siding (range: 0–1);
• A—Attractiveness of the location (range: 0–1);
• C—Regional transport potential (range: 0–1);
• Weights—α = β = γ = 1/3.

These parameters are used to calculate the RVI as a weighted average of the three input factors, reflecting the overall reactivation potential of each railway siding.

Attractiveness of the location (A) reflects the accessibility, connectivity, and logistical relevance of a siding’s location. The A value was assigned based on multiple criteria that capture the spatial and operational advantages of each site. The most important factor was the distance to the nearest connection point with the national railway network (ŽSR); sidings that are directly connected and technically maintained scored highest. Road accessibility was also evaluated, especially proximity to major roads and motorways, which supports efficient multimodal transport solutions.

Table 4. Sample evaluation of sidings using the Reactivation Value Index (RVI).

Siding	TS	A	C	RVI	Recommendation
Siding A	0.6	1.0	0.8	0.80	High potential
Siding B	0.7	0.6	0.5	0.60	Potentially suitable
Siding C	0.4	0.5	0.6	0.50	Low priority
Siding D	0.8	0.9	0.7	0.80	High potential
Siding E	0.3	0.2	0.3	0.27	Not suitable

presents a model evaluation of five sidings using the Reactivation Value Index (RVI), which incorporates three key indicators: technical condition (Ts), attractiveness of location (A), and regional transport potential (C). The calculated RVI scores serve as a decision-making tool for prioritizing siding reactivation and guiding the allocation of public support. Another important factor was whether the siding is located within an active industrial or logistics park, which increases the potential for its reactivation. The urban and regional planning framework was also considered—specifically whether the siding lies within an area designated for industrial, logistics, or development functions in local or regional planning documents. Finally, the proximity to intermodal terminals or logistics hubs was evaluated, as this is crucial for enhancing supply chain efficiency and supporting combined transport solutions.

C (Regional Transport Potential) indicates the level of potential demand for rail freight transport in the vicinity of a given siding. It was determined based on a combination of several factors reflecting transport needs and economic activity in the area.

The primary criterion was the density of road freight transport in the region, based on publicly available transport statistics from the National Motorway Company, the Transport Authority, and the Slovak Statistical Office. Additionally, the number of active industrial enterprises within a 10 km radius was considered, representing potential users of the siding infrastructure. The demand for the transport of raw materials or goods in the area—derived from the local sectoral profile (e.g., construction, energy, or mining industries)—was another evaluated component.

Finally, the existence of specific potential users, such as cement plants, refineries, warehouses, transshipment points, or industrial facilities with stable freight volumes, was included.

Each factor was scored by an expert panel on a scale from 0 to 1. The final value of C was determined as either the arithmetic mean of the scores or a weighted average in cases where certain factors had higher strategic importance for a particular location.

The results show that sidings located in economically strong regions with well-maintained infrastructure and active railway connections (e.g., Žilina, Bratislava) have the highest reactivation potential. In contrast, sidings with low RVI scores (e.g., Trebišov) show a combination of poor technical condition and low location attractiveness, making them less suitable for inclusion in public support programs. This model confirms the practical utility of the Reactivation Value Index (RVI) as an objective tool for selecting projects for reactivation within national transport and environmental policy frameworks.

• Modeling Through Indexes

The model enables (

Table 5. Projected transport performance of reactivated sidings (2026–2028).

Year	Reactivated Sidings	Expected Rail Volume (t/year)	Replaced Trucks (20 t)
2026	10	80,000	4000
2027	20	160,000	8000
2028	30	240,000	12,000

) a straightforward simulation of various development scenarios over time, based on the number of reactivated sidings and their expected performance. The following table presents an example simulation, assuming an average of 10,000 tonnes per year per siding and a utilization rate of 80%.

This model can serve as an input tool for environmental and transport planning, as it allows for not only the estimation of freight volumes, but also the projection of potential emission savings and the reduction in road network load.

• IEV (Index of Siding Efficiency) a ICV (Index of Comprehensive Value)

To verify the applicability of the proposed indices, a model-based application of the Siding Efficiency Index (IEV) and the Siding Comprehensive Value Index (ICV) was carried out using aggregated data on siding service operations across five operational centers in 2024. For each center, publicly available data on the number of performed (O_v) and planned (O_d) siding services were used. In addition, expert-assigned values for the cost coefficient (K_n) and the value coefficient (K_v) were applied, reflecting the technical and economic complexity of operations as well as the strategic importance of the given region for rail freight transport.

The results show (

Table 6. Quantitative evaluation of operational centers using IEV and ICV indexes.

Operational Center	Ov (Performed)	Od (Planned)	Kn	Kv	IEV	ICV
Bratislava	5442	5140	1.10	1.3	1.16	1.51
Košice	7921	3864	1.20	1.5	2.46	3.69
Zvolen	3839	1386	1.00	1.1	2.77	3.5
Žilina	4924	1339	0.95	1.0	3.49	3.49
Other	1222	161	1.00	0.8	7.59	6.7

) significant differences between individual operational centers. For example, the Žilina center achieves the highest efficiency (IEV = 3.49), which means that despite the relatively low number of planned services, the actual use of sidings is significantly higher. After factoring in the strategic importance of regions, the highest ICV value (6.70) appears in the “Other” category. However, due to the very low absolute number of services, this may refer to a specific siding with a unique usage regime (e.g., high frequency or strategic service to a single large enterprise).

In contrast, the Bratislava region shows slightly above-average efficiency (IEV = 1.16) and importance (ICV = 1.51), and can serve as a benchmark when setting threshold values for support.

These results confirm that the combined use of the IEV and ICV indices enables transparent, quantitative, and regionally differentiated assessment of the suitability of sidings for inclusion in a system of public support—such as tax incentives, investment grants, or strategic technical assistance.

• Expert-Based Weighting and Sensitivity Considerations

The expert evaluation in this study was based on individual assessments conducted with selected specialists from railway infrastructure management, freight operations, and transport policy authorities. Each expert independently assigned weights to the six main criteria (technical, economic, operational, environmental, legal, and socio-economic) and scored the sub-criteria using clearly defined scales. This approach ensured that no single expert influenced the opinions of others, reducing the risk of group bias. The average of these individual weightings and scores was used as the basis for calculating the indices RVI, IEV, and ICV.

To verify the robustness of the index results, a basic sensitivity analysis was conducted, in which the assigned weights of the main criteria were adjusted by ±10%. The analysis showed that in 85% of cases, the ranking of the top five sidings remained unchanged, and in all cases, the top three positions were preserved. This indicates that the model is stable and not overly sensitive to small changes in the weighting system.

As an initial step toward broader applicability, the methodology was also individually reviewed by selected experts, who confirmed that the model’s structure is clear, adaptable, and practical for real-world conditions. Future research should expand this validation to a wider group of stakeholders, including private siding operators and regional logistics planners, to further verify usability and refine the weighting scheme based on empirical testing.

7. Discussion

The proposed model of public support for railway sidings integrates legislative, analytical, and infrastructure-based approaches aimed at fostering their revitalization and more effective integration into the freight railway transport system [6,20,24]. The findings confirm the working hypothesis that there is significant potential—estimated at the modal shift of over 300,000 tonnes of freight annually if just 5% of existing sidings are reactivated—to activate transport infrastructure through indirect support instruments such as tax reliefs, as well as through state information and planning tools, including central databases and evaluation indices [25].

The sustainability dimension of siding reactivation is particularly evident in its potential to reduce road freight traffic. Every tonne–kilometer shifted from truck to rail reduces CO₂ emissions by an average of 40 g, alongside lowering particulate matter, nitrogen oxides, and noise pollution. These benefits contribute not only to meeting climate targets but also to improving public health and reducing congestion-related costs in urban and regional environments. The integration of such environmental indicators into the evaluation framework reinforces the role of siding reactivation as a practical tool for achieving sustainable freight transport.

These results are consistent with previous research emphasizing the need to maximize existing capacities before constructing new transport infrastructure (e.g., brownfield logistics, circular planning, or railway access point support) [26]. International examples from Austria, Germany, and the Czech Republic demonstrate that systematic public support—through subsidies or cooperation schemes with industry—can successfully enhance siding utilization.

From the perspective of small-to-medium enterprises (SMEs), adoption of the proposed model may face greater barriers compared to large industrial stakeholders. SMEs are more costsensitive, and even moderate co-financing requirements can be perceived as a substantial burden. Administrative complexity, such as extensive documentation and multi-agency procedures, can also discourage participation. To make the model more inclusive, simplified application processes, reduced bureaucracy, and tailored financial incentives should be considered to engage a wider range of potential siding users.

A key methodological contribution of this study is the creation of the Reactivation Value Index (RVI), which quantitatively evaluates the suitability of specific sidings for reactivation based on technical, transport, and strategic contexts. Combined with the national database, RVI can streamline the project selection process for public funding. Together with the Siding Efficiency Index (IEV) and Integrated Contribution Value (ICV), these original indices—developed specifically for this research—offer a structured, multi-perspective assessment framework that supports transparent and replicable decision-making.

Simple mathematical models were also developed to quantify potential transport and environmental benefits of siding reactivation [27]. Simulations indicate that reactivating just 5% of existing sidings could shift hundreds of thousands of tonnes of freight annually from road to rail, reducing emissions, improving safety, and relieving road network pressure [28].

To ensure methodological robustness, a sensitivity analysis of RVI weighting coefficients (α, β, γ) was conducted. The results confirmed that the index remains stable under moderate variations, while allowing targeted adjustments to reflect regional or national priorities. This adaptability strengthens the model’s transferability across diverse legal frameworks, infrastructure conditions, and market environments.

Despite its potential, its practical implementation may face challenges. Regulatory barriers—such as complex zoning laws, lengthy permitting processes [29], and strict safety compliance—can delay projects. Funding gaps may arise when subsidies do not cover full investment needs, particularly for SMEs with limited capital [30]. Addressing these challenges requires streamlined regulations, clearer safety certification guidelines, and hybrid funding models combining public and private resources.

Future research should focus on refining economic efficiency assessments, analyzing business decision-making in siding investments, and exploring the digitalization of public support mechanisms.

8. Recommendations for Further Research

The findings presented in this study confirm the strategic importance of railway sidings as a key element in the development of sustainable freight transport [31,32,33,34]. At the same time, they open up space for further research, which should build on the proposed measures and elaborate them in terms of practical implementation, efficiency assessment, and integration into broader policy and infrastructure frameworks. The most important directions for future research include the following:

• Analysis of the economic return on siding reactivation—quantitative evaluation of costs and benefits, including external environmental effects (emission savings, road decongestion).
• Study of business behavior in investing in rail infrastructure—particularly in the context of perceived tax incentives and other forms of public support.
• Expansion and digitalization of the national siding database—with an emphasis on integration with GIS tools, spatial planning documentation, and open-data systems.
• Application of models and indices in real world conditions—verification of the proposed Reactivation Value Index (RVI) in selected locations, including the testing of different weighting schemes.
• Scenario simulation of siding reactivation by regions and types of goods—including the identification of suitable logistics corridors.
• International comparison of public support tools for siding infrastructure—with the aim of transferring best practices from other EU countries to the Slovak context.
• Impact of siding support on regional development—including employment, brownfield revitalization, and development of municipalities outside main transport corridors.

Incorporating these research themes into national and international research programs and projects could significantly contribute to deepening the understanding of the role of siding networks and their potential in decarbonizing and greening the transport system of the Slovak Republic [35,36].

9. Conclusions

This article presented a proposal for an integrated model of public support for railway sidings, combining legislative, informational, and analytical tools with the aim of unlocking their transport, environmental, and economic potential [37]. The main outcomes are the formulation of two key measures—tax incentives for siding reconstruction investments and the establishment of a national database of unused sidings—which can be considered both practically feasible and cost-effective solutions within public transport policy [38].

The proposed Reactivation Value Index (RVI) offers a quantitative framework for assessing the eligibility of specific sidings for support and enables systematic decision-making by public authorities. The performance calculation model demonstrates that even the reactivation of a small share of the siding network can lead to a significant modal shift from road to rail, with substantial benefits in emission reductions, road network relief, and increased transport safety [39,40].

A key contribution of this study is its interdisciplinary scope [41]: it highlights that siding support is not merely a transport issue, but is closely linked to regional development, environmental policy, industrial investment, and the digitalization of public decision-making [33,42]. The results are thus relevant not only to transport policymakers but also to spatial planners, environmental analysts, and logistics investors.

In conclusion, railway sidings represent a vital yet underutilized [33,42,43] part of the rail infrastructure. Their targeted reactivation—supported by economic incentives, digital tools, and analytical evaluation—has the potential to become a significant component of the transition toward sustainable and climate-responsible freight transport in the Slovak Republic safety [44,45].

The proposed model is designed to be adaptable to varying conditions across EU Member States [46]. While the Slovak case study reflects a specific combination of legal, institutional, and operational factors, the methodology can be applied in countries with different regulatory frameworks and rail ownership structures. For instance, in countries where rail infrastructure is owned and managed entirely by the state, the legal and investment criteria may require fewer adjustments compared to markets with liberalized access and multiple infrastructure managers. Similarly, state aid schemes vary widely—from direct grants in Austria and Germany to tax incentives in France—requiring modifications in the economic and legal sub-criteria. By adjusting the weighting of criteria and integrating country-specific data sources, the model can effectively support strategic siding revitalization planning in both highly centralized and fully liberalized rail systems. This flexibility underlines its value as a decision support tool across diverse European contexts.